Prefabricated step unit



P 5, 1939- s. A. ROSENBERGER PREFABRICATED STEP UNIT Filed July 20, 1938 1N VENTOR.

ATTORNEY.

Patented Sept. 5, 1 939 t l 7 UNITEDSTATES PATENT OFFICE PREFABRICATED STEP UNIT Smith Alonzo Rosenberger, Valparaiso, Ind. Application July 20, 1938, Serial No. 220,275

3 Claims. (Cl. 72-96) My invention relates to improvements in precentral stringers may be bolted to each other in fabricated step units and the forms therefor any desirable manner. and it more especially consists of the features The risers 2 and the stringers 3 are held in pointed out in the claims. engagement with each other by means of bolts The purpose of my invention is to prefabricate 4 cast into the cement. Angle plates 5 fit 5 and standardize the required parts of step into the adjacent corners and pass over the bolts structures so that stringers of predetermined 4 Where they are held by nuts 6. Atthe rear end lengths with fastening bolts enbedded therein, of the stringers 3 the shortest one 7 at the top and corresponding lengths of risers and the reand the longest 8 at the bottom are held a ainst quired length of treads may be made up of vertical displacement by angle bars 9 that are 10 cement or any other material and stocked for secured to the stringers by cast in bolts 4. future sale; that may utilize cooperating forms At the top, an angle plate 5 is placed against the in which to cast the members so that the same stringer and the angle bar 9 against the plate 5. form with exchangeable end blocks will serve The bar lies against all the stringers occurring both for the risers and stringers; that may successively below the top one. Bolts 4 hold it 15 use another form with adjustable ends for the to each stringer, a duplicate angle bar is placed treads; and that optionally may use standard inside the other group of stringers in the same sized angle plates for tying the stringers to the Way and in case a pair of stringers are used in risers; and that also provides a templet for dethe center of a long step a bar 9 is placed alongtermining the location of the fastening bolts in side of each group of stringers. In such an event 20 the stringers and the risers. long trough bolts would be used instead of the A further advantage of my invention lies in cast in bolts 4. Similarly the angle plates 5 the simplicity of assembling the parts so that on opposite sides of a pair of stringers would be an unskilled person can complete a step of a deheld by trough bolts long enough to pass through sired number of treads. After the risers and both sets of stringers. 25 stringers are assembled on a suitable concrete- The stringers 3 have beveled front ends I3, cement foundation, the treads without any fasand the risers 2 are similarly beveled at M. tenings rest on the stringers and risers. The treads I are held in place by their own With these and other ends in view I illustrate weight. The underside projection I5 at its front in the accompanying drawing such instances of edge abuts risers 2 and the ends of the projec- 30 adaptation as will disclose the broad invention tion [5 hold the treads against endwise move- Without limiting myself o the Sp c fic de a ment because the projection drops below the top shown thereon and described herein. face of the adjacent riser and stringers. It is 1 is fractional front View w p t obvious that my preformed step may, if desired,

moved. be assembled without the use of any fastening 5 Fig. 2 is a side elevation with the nearest means, due to the Weight of the treads, stringers m v d to S OW t e nde neath An advantageous feature of the complete step structure. made up in accordance with my invention will 3 is a top plan view with parts removed. maintain its stability and assembled relation re- In practicing my invention I may use whatgardless of extremes of temperature. The bolts, ever equivalences and adaptations of structure nuts, angle plates and angle bars if used may be tha t e e e S 0f Varying e d t e e ey galvanized or formed of rust-proof iron and if de a d W u d pa from t bread f desired the angle plates may have the holes for tures of the invention. the bolts either slightly elongated or of a slight- The component parts of the structure will be 1y larger diameter to admit of adjustment in 45 first described. A prefabricated step includes assembling the step members or while in use. as ma y t eads l a the e ar r sers 2 nd there In addition any underside projection of the treads are twice as m y stringers 3 f v ry ng len h may have a certain tolerance of clearance at as there are rise s and tread Sh Step the front edge and the ends to allow for expanof extra width be desired a, pair of stringers will i ho ld u h be found necessary.

be placed at the center, lengthwise of the step What I c1aim is:

(not shown) and of course a stringer at each 1 As new t-1 ,1 of manufa tu e prefabrjend. Each tread at the center will be shortened cated component parts of a composition step the amount of the us a overhang S that t e WO which include a unitary tread portion, having 5 treads will abut each other lightly. The pair of an underside projection, a unitary riser member,

a plurality of cooperating stringers, and means for holding the parts in assembled relation with the under projection of the tread in approximate contact with the inside face of a riser and a pair of stringers to position the stringers in spaced apart relation.

2. A prefabricated tread member for assembly on interconnected stringers and risers, and an underside projection of the tread adapted to position it between a pair of stringers and to the rear of the riser whereby the tread is maintained in position by reason of its inherent weight.

3. In a unitary composition step, a plurality of stringers, completely beveled front ends thereon, a plurality of risers, partially beveled ends on the risers, means for assembling a riser and two stringers with their beveled ends adjacent each other, cast in bolts projecting from the inner faces of the stringers and the riser, angle plates provided with holes to receive the bolts, and nuts to hold the plates against the stringers and risers.

SMITH ALONZO ROSENBERGER. 

